This invention is directed to connectors, and more particularly, to a connecting device including one of a compressible outer member and an expansible inner member, wherein at least one of the outer member is compressible into engagement with the inner member and the inner member is expansible into engagement with the outer member, both via the application therein of a tapered member, and wherein upon either the compression of the outer member or the expansion of the inner member via the tapered member, an outer surface of the inner member is caused to engage an inner surface of the outer member for forming a firm connection. Variations on this design include the use of various thread types for preventing galling with regard to the threaded connection between the tapered member and the inner member; a multi sided inner member; and an inner member including a key which is expansible into a keyway of the outer member for achieving secure engagement.
Connections between connectable elements can be achieved using a large variety of different methods and mechanisms. The most basic connectors are screws, nails, rivets, etc. However, in many cases, these connecting devices are not applicable or desirable due to the limited engagement that they provide and also due to their tendency to interfere with the use and/or operation of the elements being connected. Accordingly, for various different operations, a plurality of connectors has been designed for relieving some of these difficulties with the more simple connectors. One category of such connectors includes those having an outer surrounding member and an inner expansible member adapted to be expanded and engaged with the outer member for achieving the connection.
The following references, for example, disclose various connection devices generally including an expansible inner member and a surrounding outer member.
U.S. Pat. No. 4,892,007 to Haldric et al. disclose a device for coupling a wheel to its shaft and further for the keying of an automobile steering wheel. The device includes complimentary and cooperative male and female connection parts. One of the parts is defined by a hub integral with a wheel while the other part is carried by an end part of a shaft which is configured to define a series of cylindrical peripheral bearing surfaces. Between the bearing surfaces are provided radial abutments which define projections. This centrifugal expansion device is adapted to be disposed directly and at least partly in the end part so as to produce a radial expansion of the series of male bearing surfaces so as to achieve immobilization of the hub via the friction caused between the end part and the hub, thereby locking the same against rotation.
U.S. Pat. No. 4,940,356 to Hashimoto et al. disclose a construction for adjoining a chain stay and seat pipe to a rear dropout in a bicycle frame. The invention includes a joint of a bicycle frame which comprises a rear dropout body having projections therefrom which decrease in taper as they extend away from the body. Each projection defines an elongated screw hole extending along a longitudinal axis of the projection. The projection also defines slits extending on both sides of the screw hole. Chain stay and seat stay pipes are provided so as to surround the projection. The chain stay and seat stay pipes have gradually decreasing diameters toward the base end of the projection. A screw or wedge is provided for insertion into the screw hole to enlarge the outside circumference of the projection until it fixedly contacts the interior of the chain stay and seat stay pipes. In addition, an adhesive agent is preferably spread around the projection of the rear dropout body and inside the chain stay and seat stay pipes for supplementing the frictional connection.
U.S. Pat. No. 3,776,651 to Peter et al. disclose a hub connection for use with hollow shafts. Briefly, the Peter et al. device includes a shaft 7 for connection with a hub 8 through the expansion of inner members 1 and 4 inside shaft 7 by turning a screw 5 therein. Upon the expansion of inner members 1 and 4, shaft 7 is expanded into locking engagement with hub 8.
U.S. Pat. No. 5,253,947 to Petrzelka et al. disclose a connection for use between a tubular shaft made of a fiber composite material and a metal journal. The invention generally relates to a locking connection for transmitting torque in drive shafts. An internally and/or externally positioned metallic connecting element having a hub journal is inserted into or slid onto a tubular shaft made of a fiber composite material. The wall of the hub journal is radially plastically deformed by the application of pressure or via an expanding mandrel, for example, directed into a cavity of the internal connecting element, for forming the connection.
The prior art in general, directed to connectors having an outer member and an inner expansible member, and particularly, the patents discussed above, are deficient for a variety of reasons. For example, those connecting devices which use an expansion means having a threaded connection with the inner member generally use standard 60.degree. threads which tend to gall and bind. Such galling and binding are even more prevalent in taper thread applications. Accordingly, in such cases, i.e., the amount of expansion force is limited. Also, in many cases, such as in Hashimoto et al., the force acquired through expansion of the inner member is not evenly distributed to the outer walls of the inner member for achieving the uniform application of force against the outer member. Also, most of the prior art connectors of this type are circular or cylindrical in shape, thereby not in themselves taking advantage of the additional anti slip characteristics available using different shapes, not shown in the prior art. Further, the gradually increasing frictional force achieved through the use of a full-length, gradually tapered means is not achieved by the prior art devices. And also, the added locking feature of cooperative expandable keys and receiving keyways for use with, most particularly, circular inner members, is not taken advantage of in the prior art. Additional drawbacks in the prior art will become further apparent below in the detailed description of the present invention.
There exists a need, therefore, for a connecting device which cures the defects of the prior art so as to connect connectable elements in a uniform manner, which prevents thread galling, and which includes supplemental anti rotation and/or anti slippage features.